From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id A20A98D0039 for ; Thu, 17 Feb 2011 23:36:12 -0500 (EST) Date: Thu, 17 Feb 2011 20:36:47 -0800 (PST) Message-Id: <20110217.203647.193696765.davem@davemloft.net> Subject: Re: BUG: Bad page map in process udevd (anon_vma: (null)) in 2.6.38-rc4 From: David Miller In-Reply-To: References: Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: torvalds@linux-foundation.org Cc: ebiederm@xmission.com, eric.dumazet@gmail.com, opurdila@ixiacom.com, mingo@elte.hu, mhocko@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org From: Linus Torvalds Date: Thu, 17 Feb 2011 20:30:42 -0800 > On Thu, Feb 17, 2011 at 7:16 PM, Eric W. Biederman > wrote: >> BUG: unable to handle kernel paging request at ffff8801adf8d760 >> IP: [] unregister_netdevice_queue+0x3a/0xb0 > > Yup. That's the "list_move()". The disassembly is exactly what I'd > expect from __list_del(): > > 16: 48 8b 93 a0 00 00 00 mov 0xa0(%rbx),%rdx > 1d: 48 8b 83 a8 00 00 00 mov 0xa8(%rbx),%rax > 24: 48 8d bb a0 00 00 00 lea 0xa0(%rbx),%rdi > 2b:* 48 89 42 08 mov %rax,0x8(%rdx) <-- trapping instruction > 2f: 48 89 10 mov %rdx,(%rax) > > So I think we can consider this confirmed: it really is the stale > queue left over on the stack (introduced by commit 443457242beb). With > CONFIG_DEBUG_PAGEALLOC, you get a page fault when it tries to update > the now stale pointers. > > The patch from Eric Dumazet (which adds a few more cases to my patch > and hopefully catches them all) almost certainly fixes this rather > nasty memory corruption. Eric D., please get a final version of the fix posted to netdev and I'll make sure it slithers it's way to Linus's tree :-) Thanks! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org